class A(object):

    def _deco(func):
        def wrapper(self,*arg):
            res = func(self,*arg)
            print('I\'m a a a decorator. This is fabulous, but that colour, so last season sweetiedarling')
            return res

        return wrapper
    @_deco
    def p(self):
        print(123)


class B(A):

    def __init__(self):
        pass

    @A._deco
    def p(self):
        print(321)


# b = B()
# b.p()

a = A()
a.p()